Would the new wells lower the water levels of Lake Merced or Pine Lake?
No. The project is not expected to significantly lower the water levels of Lake Merced or Pine Lake, the two naturally occurring lakes in the Westside Basin in San Francisco. The proposed well facility at Lake Merced would be designed to pump groundwater from a sandy layer between 380 and 450 feet below the ground surface, which would preclude the pumping from directly affecting the shallow aquifer feeding Lake Merced. Similarly, deeper pumping from the proposed South Sunset well facility would preclude the pumping from directly affecting the shallow aquifer feeding Pine Lake. A network of groundwater monitoring wells surrounding Lake Merced and near Pine Lake has been in place since 2001 or earlier, and we have been collecting data on groundwater levels from those wells since then. This monitoring network would allow us to assess how the shallow aquifer is responding to the groundwater supply project, and to adapt our usage accordingly.
